1. Field of the Invention
This invention relates to ground anchors and more specifically to devices and methods for pivoting, setting and loading driven ground anchors.
2. Background
Ground anchors or earth anchors of the driven and pivoting or tilting type are well known and generally include a main body portion having a leading edge adapted to be driven into the ground by a drive rod, a trailing edge including an outturned lip and a tensioning connection such as a cable rod or guide wire attached to a point intermediate the leading and trailing edges generally positioned from about the midpoint of the overall length of the anchor or towards the trailing edge. Upon exertion of a withdrawal force on the cable, rod or wire (herein cable), after driving of the anchor into the ground, the trailing edge outturned lip will bite into the earth causing the anchor to rotate or pivot to a set position generally at a right angle to the wire attached to the anchor.
In order to apply a force to the tensioning connection member, whether it is a rod end attached to the anchor or a cable or a guide wire, structures capable of applying an upward pull are used. It will be understood that throughout this specification and in the claims that the terms upward, vertical, horizontal or the like are used to describe the respective directions when the anchor is driven downwardly into the ground from a generally horizontal surface. Such terms should be understood to apply respectively to other orientations where, for example, the anchor may be driven into the ground at an angle and where the tension force applied to the anchor will be applied at an angle to the horizontal, or even those situations where the anchor is driven horizontally into the ground, for example when setting a revetment or retaining wall. It is therefore intended that directional terms used in this document are relative dependent upon the installation and such terms should be construed appropriately to each differing installation. These structures may range from simple hand grasped devices to pull up on the cable of small anchors to high pressure hydraulic ram structures for use with large anchors. Such driven pivoting anchors are available from the assignee of this application, Foresight Products, LLC, of 6430 East 49th Drive, Commerce City, Colo. 80022, and range in size from small Duckbill® anchors (trademark of Foresight Products, LLC), which may be only a few inches in length, to large Stingray® and Mantaray® anchors (trademarks of Foresight Products, LLC), which may have a side-to-side span of a foot or greater in length and an axial length greater than a foot, and which may require the application of 10 to 20 tons of tensioning force to proof test the holding power of the anchor.
For small to medium size anchors, however, rotation of the anchor setting and loading locking it has generally been accomplished by relatively unsophisticated and tension force pressure guessing means. It has been common, for example, to use automobile ratcheting car jacks over which a cable has been looped and then tied to the ends of the anchor cable so that upon ratcheting of the car jack the moving jack member will pull up on the anchor cable. Obviously when the car jack, being hand operated, is no longer moving easily, it can be said that the anchor setting has been proof tested, however there is no measurement of the force applied, and that force will vary considerably depending upon the length of the lever arm used to operate the jack and the strength of the person pressing down on the lever arm.
While hydraulic ram devices can be equipped with pressure cages to give an instantaneous readout of the pressure applied to the anchor cable or rod, as the case may be, generally for smaller mechanical or hand operated tension loading devices it has been difficult to determine when the anchor has been tested to its desired set point.
It would therefore be an improvement in the art to provide an inexpensive anchor setting, locking, loading, and proof testing structure and method of load locking and proof testing of such driven rotatable earth anchors.